Using ab
initio band structure results of five donor-acceptor polymers, the
electronic structure and conduction properties of their novel binary copolymers
have been investigated. One of the donor-acceptor polymers based on thiophene
(PCNTh) is common in all the copolymers while second one is varied by replacing
S atom with CF2, O, SiH2 or CH2 respectively.
The effect of substitution on the electronic properties of the copolymer is
investigated. In order to calculate the electronic properties of the copolymers
and to obtain the copolymer possessing minimum band gap, genetic algorithm is
used along with negative factor counting and inverse iteration technique. The
copolymer containing CF2 units is found to have the lowest band gap
and hence maximum intrinsic conductivity. Investigations involving variation in
block sizes of the homopolymer units suggest that copolymers containing lower
concentration of PCNTh are better candidates for both intrinsic as well as
extrinsic conductivity.